The building and compound is not heavily secured so it rules out this spot as a military AOI. It's probably a spot where the emulsion from the original negative was scraped off accidentally. Sun light wouldn't reflect at right angles and have a crisp boundary as in this image. If it was a remote sensor then you would see a streak where the scanner was "over charged" and then regains it's composure, kind of like the flash bulb effect when taking pictures.

From: Shadrack
Wed Oct 24 04:36:32 -0700 2007

Take a look at this Google map of Qingdao in China. You will see the same effect but multiplied hundreds of times. It is a reflection from the Sun.